JP4592444B2 - Tapered roller bearing - Google Patents

Description

  The present invention relates to a tapered roller bearing used for a shaft support portion of an automobile transmission or a differential.

Tapered roller bearings used in shaft supports for automobile transmissions and differentials are usually used with preload applied to ensure rigidity, to ensure proper contact with the gear, and to ensure bearing life. The However, in recent years, aluminum alloys are generally used for transmission and differential cases for weight reduction, and their linear expansion coefficient is larger than that of shafts and bearings made of steel in terms of strength. Therefore, preload loss (clearance state) often occurs during high temperature operation.
In addition to this, low-viscosity oil tends to be used as a lubricant for AT / CVT (automatic transmission, continuously variable transmission) and fuel efficiency reduction of transmission, and downsizing of transmission -The use environment tends to increase the load and temperature due to the higher output, so the degree of preload loss and the operating environment at that time tend to be severe.
As a result, even if the preload is set as shown in FIG. 4 (A), a large shaft inclination acts when the conical bearing 11 is in a clearance state as shown in FIG. 4 (B) during operation at a high temperature. As a result, edge contact with the roller 14 occurs on the small diameter side of the raceway surface 13a of the outer ring 13, and the outer ring outer ring raceway surface 13a may peel off from the small diameter side edge portion in a very short time.

As a proposed example to prevent preload loss, in a tapered roller bearing used for a shaft support part of an automobile transmission or a differential, a ring groove is provided on the surface facing the bearing width surface of the case supporting the bearing, and the ring groove is made of steel. There exists what makes a made ring member fit (patent document 1). In addition, as a proposed example of reducing the edge surface pressure under misalignment, a carbonitriding layer is formed on the surface of each part of the outer ring, inner ring, and tapered roller, and crowning is formed on both ends of the inner ring raceway surface. Yes (Patent Document 2).
JP 2000-192978 A JP 2000-161348 A

  However, in the configuration disclosed in Patent Document 1, it is necessary to process a ring groove or add a steel ring member to the case. In the configuration disclosed in Patent Document 2, it is necessary to form a carbonitriding layer on the surface of each component. For this reason, there is a problem that both increase costs.

  The object of the present invention is to suppress the early peeling of the outer ring small-diameter edge that occurs when the shaft tilt occurs in the clearance state due to the preload loss, and to suppress this, the processing and processing do not increase and the increase in cost can be suppressed. It is to provide a tapered roller bearing.

The tapered roller bearing according to the present invention is a tapered roller bearing having an assembly part at an inner ring and a part corresponding to an outer ring or an outer ring, and constitutes an outer ring raceway surface which is a raceway surface of the part corresponding to the outer ring or the outer ring. The cone angle of the outer ring raceway surface is smaller in the range of 2 minutes or more and 7 minutes or less with respect to the vertex angle of the cone surface circumscribing the roller train in the assembly part of the inner ring . the rollers are in contact with the large diameter portion, and wherein the this gap is formed between the outer ring raceway surface in the small diameter portion of the outer ring raceway surface and the roller.
According to this configuration, the inclination angle of the outer ring raceway surface is set to be slightly smaller than the angle of the inner ring / roller assembly parts. That is, the outer ring raceway surface is set so that a slight gap is formed on the outer ring small diameter side. For this reason, even if the bearing housing, for example, the transmission or the differential becomes high temperature and a gap is generated in the bearing and the shaft is inclined, the edge contact of the roller on the small diameter side of the outer ring raceway surface is eliminated. As a result, it is possible to prevent the small-diameter side edge portion of the outer raceway surface from peeling off in a very short time due to the preload loss. If the difference in the apex angle is less than 2 minutes, the outer ring small diameter side edge portion is not sufficiently prevented from peeling, and if it exceeds 7 minutes, the large diameter edge portion may be peeled off under a preload condition. There is.
Further, according to this configuration, since only the angle of the outer ring raceway surface or the inner ring / roller assembly parts is changed, it is not accompanied by an increase in processing and processing, and therefore, an increase in cost can be avoided.

In this invention, crowning may be applied to at least one of the inner and outer raceway surfaces and the outer peripheral surface of the roller.
As described above, the inclination angle of the outer ring raceway surface is set slightly smaller than the angle of the inner ring / roller assembly parts, so there is no misalignment (shaft inclination), and low temperature and low initial operation with preload applied. In the state of load, the roller comes into contact with the large diameter portion of the outer ring raceway surface. Since this state is a relatively light load, if crowning is applied to the inner and outer raceway surfaces or the outer peripheral surface of the roller, generation of excessive edge stress is prevented by the crowning shape.

  In the tapered roller bearing of the present invention, the apex angle of the conical surface constituting the raceway surface of the outer ring or a part corresponding to the outer ring is 2 to the apex angle of the conical surface circumscribing the roller row in the assembled part of the inner ring. Since it is smaller in the range of more than 7 minutes and less than 7 minutes, it is possible to suppress early peeling of the outer ring small-diameter edge that occurs when the shaft tilt occurs in the clearance state due to the preload loss, and the processing and processing increase for the suppression. Without increasing the cost.

  An embodiment of the present invention will be described with reference to FIG. The tapered roller bearing of this embodiment is used for a shaft support portion of an automobile transmission or a differential. As shown in FIG. 1A, this tapered roller bearing 1 has an inner ring 2, an outer ring 3, and tapered rollers 4 interposed between the inner and outer rings 2, 3. Axial preload can be applied. The inner ring 2 has a raceway surface 2a composed of a conical surface on the outer diameter surface, and a large collar 2b and a small collar 2c on the outer diameter side and the smaller diameter side, respectively. The outer ring 3 has a raceway surface 3 a made of a conical surface facing the raceway surface 2 a of the inner ring 2. A plurality of tapered rollers 4 are interposed between the raceway surfaces 2a and 3a so as to be freely rollable. These tapered rollers 4 are held by a cage 5 at a predetermined interval in the circumferential direction.

  The apex angle α of the conical surface constituting the raceway surface 3 a of the outer ring 3 is 2 minutes or more and 7 minutes or less with respect to the apex angle β of the conical surface circumscribing the roller row in the assembled product of the inner ring 2 and the tapered roller 4. It is set small in the range. In other words, the inclination angle of the outer ring raceway surface 3a is relative to the inclination angle of the assembled product of the inner ring 2 and the tapered roller 4 (that is, the inclination angle of the assembly part outermost diameter bus on the rolling surface of the tapered roller 4). The full width is set to be small within a range of 2 minutes or more and 7 minutes or less.

As shown in FIG. 2, the raceway surfaces 2a and 3a of the inner and outer rings 2 and 3 and the outer peripheral surface of the tapered roller 4 are both crowned, that is, a shape in which the center in the axial direction swells most and gradually becomes concave as it approaches both ends. Has been. The crowning shape may be a shape in which the cross section becomes a convex curve over the entire length in the axial direction, or a shape in which only the vicinity of both ends in the axial direction becomes a cross sectional convex curve.
The raceway surfaces 2a, 3a of the inner and outer rings 2, 3 and the outer peripheral surface of the tapered roller 4 do not necessarily have to be crowned, but at least one of these surfaces has been crowned. It is preferable to do.

  According to the tapered roller bearing 1 having this configuration, as described above, the apex angle α of the conical surface constituting the raceway surface 3a of the outer ring 3 is such that the apex of the conical surface circumscribing the roller row in the assembled product of the inner ring 2 and the tapered roller 4 is obtained. It is set slightly smaller than the angle β. Therefore, in the state of low temperature and low load at the initial stage of operation, that is, in the state of FIG. Will do. Since this state is a relatively light load, the generation of excessive edge stress is prevented by the crowning applied to the raceway surfaces 2a, 3a of the inner and outer rings 2, 3 or the outer peripheral surface of the tapered roller 4.

On the other hand, when the transmission and differential supported by the tapered roller bearing 1 are heated to high temperatures, a clearance is generated in the bearing 1 due to preload loss and shaft inclination occurs. In this state, the state shown in FIG. 1B is obtained, and the edge contact of the tapered roller 4 to the small diameter side of the outer ring raceway surface 3a as in the conventional example (FIG. 4B) does not occur. As a result, it is possible to prevent the small-diameter side edge portion of the outer ring raceway surface 3a from peeling off in a very short time due to the preload loss.
Further, in this configuration, since only the angle of the outer ring raceway surface 3a or the inner ring / roller assembly parts is changed, it is not accompanied by an increase in processing and processing, and therefore, an increase in cost is avoided.

  The following Table 1 shows the difference between the apex angle α of the outer ring raceway surface 3a in this embodiment with respect to the apex angle β of the conical surface circumscribing the roller row in the inner ring and tapered roller assembly product, and the presence or absence of outer ring small diameter edge separation. The result of testing the relationship is shown.

  From these test results, the outer ring raceway surface 3a has an apex angle α that is smaller than the apex angle β of the inner ring and tapered roller assembly by at least 2 minutes, thereby suppressing the occurrence of outer ring edge separation in a very short time due to edge contact. It was confirmed that it would be possible. The apex angle α is preferably reduced by 3 minutes or more. Further, it was confirmed that edge peeling occurred on the large diameter side of the outer ring raceway surface 3a under the condition that the preload was applied when the time was decreased to exceed 7 minutes. Therefore, a preferable angle difference is in the range of 2 minutes or more and 7 minutes or less.

FIG. 2 shows another embodiment of the present invention. The tapered roller bearing 1 of this embodiment is obtained by replacing the outer ring 3 with a gear 3A that is a part corresponding to the outer ring in the embodiment of FIG. That is, the tapered roller 4 is caused to roll with the inner diameter surface of the gear 3A as a raceway surface 3a made of a conical surface. Other configurations are the same as those in the embodiment of FIG.
In the case of such an outer ring equivalent component such as the gear 3A, the same operation and effect as described above can be obtained by providing the difference between the apex angles α and β as described above.

(A) is sectional drawing which shows the operation | movement initial stage state of the tapered roller bearing concerning 1st Embodiment of this invention, (B) is sectional drawing which shows the state at the time of high temperature operation of the tapered roller bearing. FIG. 2 is an enlarged cross-sectional view of a part of FIG. It is sectional drawing which shows the operation | movement initial stage state of the tapered roller bearing concerning other embodiment of this invention. (A) is sectional drawing which shows the operation | movement initial stage state of the tapered roller bearing of a prior art example, (B) is sectional drawing which shows the state at the time of the high temperature driving | running of the tapered roller bearing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Tapered roller bearing 2 ... Inner ring 3 ... Outer ring 3A ... Gear (outer ring equivalent part)
2a, 3a ... raceway surface 4 ... tapered roller 5 ... cage

Claims (2)

A tapered roller bearing having an assembly part on the inner ring and a part corresponding to the outer ring or the outer ring, and an apex angle of the conical surface constituting the outer ring raceway surface which is a raceway surface of the outer ring or the part corresponding to the outer ring , In the assembled part of the inner ring, the apex angle of the conical surface circumscribing the roller row is smaller in the range of 2 minutes or more and 7 minutes or less, and the roller contacts the large diameter portion of the outer ring raceway surface. A tapered roller bearing characterized in that a gap is formed between the outer ring raceway surface and the roller at a small diameter portion of the outer ring raceway surface .   The tapered roller bearing according to claim 1, wherein at least one of the inner and outer raceway surfaces and the outer peripheral surface of the roller is crowned.

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